Raise the seat higher and bring it forward a bit? Just curious how you have your seat adjusted.

Also, you can "Lock" your seatbelt so that it won't 'flop' around. To do so... tighten the lap belt by pulling near the buckle on the shoulder belt, then while holding that tight, pull the shoulder belt out and allow it to snap back quickly. This should lock your belt in place and be snug.

I know for some people while daily driving this can be uncomfortable, but it's a far sight better than having a floppy seat belt in an accident. It takes a few miliseconds and a few inches of slack for the retractors to lock in a collision. If (heaven forbid) you get in one, you want that belt holding you firmly in your seat.

Hope that helps...